Space Weather & Physics
Real-Time Ionospheric Specification Modules
1. TEC SIMULATOR
This program simulates TEC data for data for chosen ionospheric models, receiver locations and satellites. The data are similar to experimental data obtained from GPS receivers.
Ionospheric Models – PIM, IRI, Chapman, user-supplied. Any of the models can be modified iteratively. Models of blobs, patches, and irregularities are built in and can be inserted through mouse button.
Receivers, Satellites – Any location in ground, in space. Any satellite GPS, NNSS, GLONAS, or user-supplied. Max numbers 730 or more.
Errors – Noise model, multipath.
Features – MENU-DRIVEN. Extremely user friendly. 32 bit, Windows 95, GUI. Built-in visual graphics.
2. IONOSPHERIC RECONSTRUCTOR
This program takes TEC data (from a simulator or real-time receivers) and reconstructs the 4-D ionosphere over the region of interest. It has ionospheric models, receivers, satellites, and other features, similar to what is available in the simulator program. The reconstruction process uses the following techniques:
- Initial Assessment (Pre-tomography).
- Tomographic reconstruction. Various algorithms are implemented and can be chosen (if needed by the user).
- Use of expert system for initial guess.
- Use of (optional) ancillary data.
- Plasmaspheric models.
- Plasma flow modeling.
3. PARAMETER EXTRACTOR
This program takes the output from reconstructor and derives relevant ionospheric data (foF2, hmax, plasmaspheric content and scale height) in latitude, longitude, and time frames. These data can be delineated along with any real-time inputs and the differences fed back to the reconstructor program, if needed.
All the features of the TEC SIMULATOR are available with this program.
4. IONOSPHERIC PREDICTOR
This program takes measured values of ionospheric parameters (measured, simulated or derived from ionospheric reconstruction process) e.g., foF2, hmax, over a few locations and predicts the values at other locations and times. It uses an analytical physics based model for the prediction. Can be used for network of ionosondes.
This program may be used in seamless conjunction with the IONOSPHERIC RECONSTRUCTOR and PARAMETER EXTRACTOR (integrated through Windows) or it can work independently using data from ionosondes or other sources. Its features are very similar to those available with other programs.
5. PROPAGATION MODELER
This program accepts the 3-D profiles from the reconstructor and performs 3-D ray tracing for any receiver and transmitter locations. With 4-D inputs the temporal variations of propagation conditions are delineated.
This program simulates simple ionospheric profiles, calculates TECs for different satellite positions, adds noise to the TECs, and finally reconstructs 1-D and 2-D ionosphonic profiles from the TEC values. It uses various tomographic reconstruction techniques:
Results of reconstruction and associated error values are displayed in real time. This program demonstrates the accuracies, limitations, noise and numerical sensitivities, and initial guess assumptions of different algorithms.